The present invention relates to a soybean (Glycine max.) seed, a soybean plant, a soybean variety, a soybean hybrid and methods for producing hybrid soybean seed and plants.
Soybeans (i.e., seeds of Glycine max plants) are recognized to be an important crop in many parts of the world. For instance, approximately 65 to 75 million acres of soybeans are planted annually in the United States. Various approaches to the production of hybrid soybeans are disclosed in the U.S. Pat. Nos. 3,903,645; 4,077,157; 4,545,146; 4,658,084; 4,648,204 and 4,763,441 which are herein incorporated by reference. Also, technical articles which discuss the existence of some degree of sterility in soybeans and the formation of hybrid soybean seeds are identified in U.S. Pat. No. 4,545,146.
For many crop species, it is well known that when different plant lines are cross-pollinated one can achieve in the offspring a highly desirable heterosis or hybrid vigor which advantageously provides increased yields of the desired crop.
Male sterility is a condition in plants in which male gametophytic function is prevented, but the potential for female reproduction remains. Based on inheritance patterns, there are two general types of male sterility: 1) genic or nuclear male sterility (gms) and 2) cytoplasmic male sterility (cms). Male-sterile mutations provide source material for studies in plant breeding, genetics, reproductive biology, and molecular biology.
Male sterility has been used in soybean breeding studies (Brim, C. A. et al., Application of genetic male sterility to recurrent selection schemes in soybeans, Crop Sci 13:528-530, 1973; Lewers, K. S., et al., Hybrid soybean seed production: comparison of three methods, Crop Sci 36:1560-1567, 1996), but so far male sterility has not been used for commercial production of a hybrid seed because large quantities of hybrid soybean seed cannot be produced at the present time. During the past two decades, six genic male sterile mutations (ms1, ms2, ms3, ms4, ms5 and ms6) have been reported in soybean (Palmer, R. G., et al., Male sterility in soybean and maize: developmental comparisons, Nucleus (Calcutta) 35:1-18, 1992). All of these are nuclear mutations inherited as monogenic recessive traits. Cytoplasmic male sterility has not been confirmed in soybean.
Genic male-sterile mutants have been proposed for many crop species breeding programs (Horner, H. T., et al., Mechanisms of genic male sterility, Crop Sci 35:1527-1535, 1995). Controlled production of hybrid seed is necessary for breeding programs and genetic studies. The most feasible methods should utilize close genetic linkage between a male-sterility locus and a seedling marker locus. In soybean, use of the close genetic linkage (Skorupska, H., et al., Genetics and cytology of the ms6 male-sterile soybean, J Hered. 80:403-410, 1989) between a male-sterility locus and a seedling marker locus (W1) is known as the co-segregation method to produce F1 seeds (Lewers, K. S., et al. supra). The identification of additional soybean genic male steriles linked to a seedling marker locus would reduce the genetic vulnerability of soybean production of a single genic male sterile.
G. Marrewijk, Cytoplasmic male sterility in petunia l. Restoration of fertility with special reference to the influence of environment, Euphytica 18:1-20 (1969), reported that the phenotypic effect of partial male-sterility systems was subject to environmental modifications. Temperature has more influence than any other environmental factor: however, water stress, photoperiod, nutrients supplied, and hormone applications also influence male sterile phenotypes (Heslop-Harrison, J., The experimental modification of sex expression in flowering plants, Biol Rev 32:38-90, 1957; Edwardson, J. R., Cytoplasmic male sterility, Bot Rev 36:341-420, 1970). In soybean, the msp mutant is affected by temperature (Stelly, D. M., et al., A partially male-sterile mutant line of soybeans Glycine max (L.) Merr.: characterization of msp phenotype variation, Euphytica 29:539-546, 1980; and Carlson, D. R., et al., Effect of temperature on the expression of male sterility in partially male-sterile soybean, Crop Sci 25:646-648, 1985).
The male-sterile soybean mutants ms2 and ms3 result in a degeneration of tetrads because release of microspores from their encasing callose walls is prevented, a phenomenon also described in other, non-legume, species. For example, the failure of callose to break down at the proper time in cms petunia anthers resulted in sterility (Frankel, R. et al.,Timing of callase activity and cytoplasmic male sterility in petunia, Biochem Genet 3:451-455, 1969). The retention of callose seemingly blocks developmental metabolic processes (physical constraints are imposed by the callose wall) and intercellular communication between male cells and locular fluids and between male cells and surrounding tissues.
Examples of widely used herbicides are chlorimuron and thifensulfuron, which belong to the sulfonylurea class. They inhibit the plant enzyme acetolactate synthase (also called ALS), and soybeans which are resistant to these herbicides are referred to as STS (also called sulfonylurea tolerant) soybeans. These herbicides are the active ingredients in Classic(trademark) and Pinnacle(trademark), respectively, and are registered for control of broadleaf weeds in soybeans in Weed Science Society of America, Herbicide Handbook, 7th edition (1994). While chlorimuron and thifensulfuron are registered for use in non-STS soybeans, they can cause significant crop injury, especially if applied post-emergence in Fielding and Stoller, Weed Technol. 4:264-271 (1990); Fielding and Stoller, Weed Sci. 38:172-178 (1990); Newsom and Shaw, Weed Sci. 42:608-613 (1994); and Ahrens, Weed Technol. 4:524-528 (1990). Factors which influence the extent of herbicide injury are physiological stresses from poor seed quality, delayed emergence in cold and wet soils, seedling diseases, etc.; soil pH and climatic conditions (i.e. temperature and humidity) when applications are made; and injury from prior applications of chemicals (e.g. insecticides and other herbicides).
Glyphosate, which belongs to a different class of herbicide and is the active ingredient in both Roundup(trademark) and Roundup Ultra(trademark), complements activity of the other herbicides (e.g. 2,4-D and dicamba). In some cases, glyphosate interacts synergistically with these other herbicides when they are applied in combination, as shown in Moshier, Weed Sci. 28:722-724 (1980) and Flint and Barrett, Weed Sci. 37:12-18 (1989). Tank mixing Classic(trademark) at 0.5 oz/A or Pinnacle(trademark) at 0.125 oz/A with Roundup(trademark) at 16 fl oz/A increases control of broadleaf weeds but, in the case of Pinnacle(trademark), injury of Roundup Ready(trademark) soybean is greater with the combination than with Roundup(trademark) alone as discussed in Lich and Renner, Proc. NCWSS 50:124 (1995). Combination of Roundup Ultra(trademark) with Synchrony(trademark) (premix of chlorimuron plus thifensulfuron at elevated rates) effectively controls a broad spectrum of weeds.
For a number of technical and practical reasons, resistance to herbicides in agronomically important crops was among the first traits to which recombinant DNA technology and novel genetic approaches were applied. The advent of Roundup Ready(trademark) (RR) Soybeans which have a level of resistance to glyphosate, and Liberty Link(trademark) (LL) Soybeans which have a level of resistance to the herbicide glufosinate has provided new opportunities in agriculture. This technology has allowed developers of soybean varieties to build herbicide selectivity and true crop safety mechanisms into soybean. This approach thus has expanded the utility of proven, previously non-selective, broad spectrum herbicides. These herbicide resistant crops enable improved weed control and greater flexibility in herbicide application, resulting in better production systems. New herbicide resistance traits can be developed as components of new weed control systems featuring herbicides with the beneficial environmental characteristics needed to meet current and future rigorous demands on active ingredients.
A major obstacle to F1 hybrid soybean seed production is the intensive hand-labor requirement for large numbers of pollinations. Significant heterosis was observed in Production and Performance of Hybrid Soybeans, Nelson, R., et al., Crop Science (1983) p. 549, even though relatively few hybrids were tested and the parents were unselected for combining ability. The inability to produce large quantities of hybrid seeds economically is the major barrier to the use of commercial hybrid soybean cultivars.
A process is provided for the efficient production of seeds capable of growing F1 hybrid Glycine max comprising:
a) planting seed of a male sterile female parent line, having a male sterile gene linked to a herbicide resistance gene, adjacent to seed of a male fertile male soybean variety;
b) allowing male sterile female soybean plants to cross-pollinate with male fertile soybean plants with the aid of pollen-carrying insects;
c) spraying with said herbicide to kill non-resistant pollen and plants; and
d) harvesting F1 hybrid soybean seed.
It is an aspect of the present invention to develop male sterile female parent lines having a nuclear male sterile gene linked to a herbicide resistance gene.
It is another aspect of the invention to mix seed of the male sterile parent line with another male fertile soybean variety to produce a seed mixture. This seed mixture can be planted in a production field or greenhouse to produce hybrid seed.
The invention further relates to a soybean plant having a level of resistance to glyphosate or Roundup(trademark) herbicide or sulfonylurea or STS(trademark) herbicide, or glufosinate or Liberty(trademark) herbicide or protoporphyrinogen oxidase inhibitors or Acuron(trademark) herbicides.
It is an aspect of the present invention to provide a process for producing seed capable of forming F1 hybrid soybean plants using a male sterile gene linked to a herbicide resistance trait.
It is another aspect of the present invention to provide a process for maintaining male sterile soybean plants useful in the production of male fertile F1 hybrid soybean plants wherein pollen-carrying bees or other insects are employed to accomplish the required pollen transfer.
It is a further aspect of the present invention to provide a process for producing seeds capable of forming F1 hybrid soybean plants.
These and other aspects as well as the scope, nature, and utilization of the claimed invention will be apparent to those skilled in the art from the following detailed description and appended claims.
In the description and tables which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided:
Male sterile genexe2x80x94As used herein, xe2x80x9cmale sterile genexe2x80x9d refers to any nuclear or cytoplasmic gene which confers the male sterile (MS)characteristic to the plant.
Maintainer line or seedxe2x80x94As used herein, xe2x80x9cmaintainer line or seedxe2x80x9d refers to a male fertile soybean line which is then crossed onto the same or similar line having the male sterile gene. This cross produces male sterile seed.
Isolinexe2x80x94As used herein, xe2x80x9cisolinexe2x80x9d refers to a line, derived from backcrossing with a recurrent parent, but still retaining a trait of interest from the xe2x80x9cdonorxe2x80x9d parent. For example, the isoline xe2x80x9cA+xe2x80x9d has the characteristics of A plus the male sterile gene linked to a gene resistance to glyphosate herbicide.
Backcrossingxe2x80x94As used herein, xe2x80x9cbackcrossingxe2x80x9d refers to a process in which a breeder repeatedly crosses hybrid progeny back to one of the parents (recurrent parent), for example, a first generation hybrid F1 with one of the parental genotypes of the F1 hybrid.
Recurrent parentxe2x80x94As used herein, xe2x80x9crecurrent parentxe2x80x9d refers to the parent genotype which is repeatedly backcrossed to during the backcross breeding procedure.
Female linexe2x80x94As used herein, xe2x80x9cfemale linexe2x80x9d refers to the female parent of a hybrid.
Male linexe2x80x94As used herein, xe2x80x9cmale linexe2x80x9d refers to the male parent of a hybrid.
Nuclear male sterile genexe2x80x94As used herein, xe2x80x9cnuclear male sterile genexe2x80x9d refers to a male sterile allele or alleles which are contained within the nucleus of the cell.
Seed Setxe2x80x94As used herein, xe2x80x9cseed setxe2x80x9d means the total number of seeds on a mature plant. For example, 50% of normal seed set for a given environment means that the male sterile plants produced 50% of the number of seeds per plant compared to what is produced or expected from male fertile (selfed) soybean plants. The seed harvested from male sterile plants are F1 hybrid soybean seeds, whereas the seed harvested from selfed soybean plants are not hybrid seed but selfed seed of the soybean variety.
ALS Inhibitorxe2x80x94As used herein, the xe2x80x9cALS inhibitorxe2x80x9d means any herbicidally effective form of sulfonylureas, triazolopyrimidine sulfonamides, imidazolinones or heteroaryl ethers including any salt thereof or other related compounds or derivatives.
Atrazinexe2x80x94As used herein, the term xe2x80x9catrazinexe2x80x9d means any herbicidally effective form of triazine, including 6-40-N-ethyl-Nxe2x80x2-(1-methylethyl)-1,3,5-triazine-2,4-diamine, and including any salt thereof or other related compounds or derivatives.
Glufosinatexe2x80x94As used herein, the term xe2x80x9cglufosinatexe2x80x9d means any herbicidally effective form of phosphinothricin, including any salt thereof or other related compounds or derivatives.
Glyphosatexe2x80x94As used herein, the term xe2x80x9cglyphosatexe2x80x9d means any herbicidally effective form of N-phosphonomethylglycine including any salt thereof or other related compounds or derivatives or any other 5-enolpyrunyl 3-shilkimate phosphate synthase inhibitor. Roundup(trademark) is a glyphosate herbicide.
Herbicide Resistancexe2x80x94The term xe2x80x9cherbicide resistancexe2x80x9d means the ability to survive with agronomically acceptable injury, a concentration of herbicide that is normally lethal or extremely injurious to individual plants of a given species.
Isoxaflutolexe2x80x94As used herein, the term xe2x80x9cisoxaflutolexe2x80x9d means any herbicidally effective form of 5-cyclopropyl-4 (methane sulphonyl 1-4-thifluoromethylbenzoyl), isoxazole or other related compounds or derivatives.
Paraquatxe2x80x94As used herein, the term xe2x80x9cparaquatxe2x80x9d also known as Gramoxone(trademark), means any effective form of 1,1xe2x80x2-dimethyl4,4xe2x80x2-bipyridinium dichloride or other related compounds or derivatives.
Protoporphyrinogen oxidase inhibitors (PPO)xe2x80x94As used herein, the term xe2x80x9cprotophorphyrinogen oxidase inhibitors (PPO)xe2x80x9d means any herbicidally effective form of PPO herbicides or other related compounds or derivatives. The Acuron(trademark) gene is a herbicide tolerance gene that conveys tolerance to a broad class of PPO herbicides.
In one preferred embodiment of the present invention, a soybean line was used which contained a nuclear recessive male sterile gene such as msMOS, ATCC accession No.209344, from U.S. Pat. No. 6,046,385. Preferably, the male sterile soybean gene should result in seed set greater than 50% of the normal seed set in a field environment, when grown in the presence of effective natural soybean pollinators, or introduced pollinators, such as the alfalfa leafcutting bee (leafcutter bee), Megachile rotundata; hornfaced bees, Osmia cornifrons; or orchard mason bees, Osmia lignaria. 
Observations on the genetics and developmental reproductive biology of most of the soybean mutants have been summarized by Graybosch, R. A., et al., Male sterility in soybeanxe2x80x94an overview, Am J Bot 75:144-156 1988; Palmer, R. G., et al. supra, which are incorporated herein by reference. In soybean mutants ms2 and ms3, male sterility is due to abortion of microspores caused by failure of callose dissolution at the tetrad stage. In the present invention, a similar phenomenon was observed leading to microspore abortion in a potentially new male sterile line as described in Jin, W., et al., Genetics and cytology of a new genic male-sterile soybean (Glycine max (L.) Merr.), Sex Plant Reprod 10:13-21; 1997, which is incorporated herein by reference.
For msMOS, the genetic data indicate that the male-sterile soybean (xe2x80x9cmsxe2x80x9d) is genic male sterile (gms) and is controlled monogenically by a single recessive allele and is described in U.S. Pat. No. 6,046,385 which is herein incorporated by reference. Based on results of glasshouse breeding experiments, this is a completely male-sterile line. The mutation causing male-sterility occurs at a locus that differs from the already characterized msl, ms2, ms3, ms4, ms5, and ms6 soybean lines.
The most obvious abnormalities of tapetal cells in the soybean male-sterile mutant line of the present invention were cell enlargement, the accumulation of an unidentified, densely staining material, and premature degeneration. This accumulated material, based on its staining, is suspected to be sporopollenin or its precursors. The tapetum is regarded as the site for synthesis for precursors of sporopollenin (Echlin, P., The role of the tapetum during microsporogenesis of angiosperms. In: Heslop-Harrison J (ed) Pollen: development and physiology, Butterworths, London, pp 41-61, 1971; Horner, H. T., Jr., et al., Pollen wall and aperture development in Helianthus annuus (Compositae: Heliantheae), Am J Bot 65:293-309, 1978; and Nakashima, H., et al., Histological features of anthers from normal and ms3 mutant soybean (Glycine max (L.) Merr.), Crop Sci 24:735-739, 1984).
Table 1 lists the genic male sterile mutants other than msMOS. In many of the male-sterile mutations, abnormal tapetum activity or premature degeneration is associated with the abortion of microspores (Laser, K. D., et al., Anatomy and cytology of microsporogenesis in cytoplasmic male sterile angiosperms, Bot Rev 38:425-454, 1972; Gottschalk, W., et al., The genetic control of microsporogenesis in higher plants, Nucleus (Calcutta) 17:133-166, 1974; and Koltunow, A. M., et al., Different temporal and spatial gene expression patterns occur during anther development, Plant Cell 2:1201-1224, 1990). Table 1 Phenotypic expression of genic male-sterile, female-fertile mutants in soybean. The msMOS gene is the preferred male sterile gene in the method of the present invention.
To date, there is no known method in soybeans which results in a high hybrid seed set on the female parents in the production of F1 hybrid soybean seed. The method of the present invention allows a seed set greater than 30% of normal seed set on the female parents. This high percentage of hybrid seed set is critical for the economical production of hybrid soybean seeds.
In another preferred embodiment of the present invention, the male sterile gene is linked to a herbicide resistance gene for glyphosate (Roundup(trademark)) to allow economically segregating the male sterile plants. The male sterile gene is a nuclear gene. Using a soybean line having the linked nuclear male sterile gene and herbicide resistance, the male sterile female parents for hybrid production method of the present invention are made. In one preferred embodiment to produce male sterile elite lines, elite soybeans were crossed onto the soybean line having the male sterile msMOS gene linked with the glyphosate resistance gene. The male sterile msMOS gene is linked to the glyphosate resistance gene with a recombination ratio of approximately 11%. These crosses were made using hand pollination procedures commonly used and known by those skilled in soybean plant breeding. In the next generation, pollen from the F1 hybrid plants was crossed back to the elite female (recurrent parent). These hybrid plants are preferably sprayed with the glyphosate herbicide every ten days starting with the presence of flower buds until after pollinations are completed. The application rate should be at or just below standard recommended rates. For glyphosate herbicide, this rate is preferably 24 to 30 ounces per acre. This spray application kills the male gametes that are not carrying the herbicide resistant male sterile gene and assists in the backcrossing from the F1 and continued subsequent backcrossing to the original elite female. This procedure and backcrossing preferably continues for a number of backcross generations, preferably 4-9 backcrosses (BC) until the original line has been converted to the state of a stable near isoline. After the elite female is converted to the male sterile, one then makes larger quantities of maintainer seed and the male sterile parent seed.
In the present invention, maintainer seed consists of a male fertile line which, when crossed onto the male sterile (ms) plants, produces male sterile seed. Maintainer seed is heterozygous for the ms gene (i.e., MSms) and is developed by crossing the original soybean line (recurrent parent) onto the male sterile plants of the isoline (developed from this same soybean line via the backcrossing procedure). Initially, in order to develop a male sterile isoline, this is accomplished by planting alternate rows of the original line and the segregating progeny of F2 BC seed of the line for each backcross generation. This can be accomplished by hand pollination or preferably by insect pollinators of soybean with the fertile segregants of the F2 BC rows being removed by hand as they begin to flower. The initial flowers on each plant are checked and tagged as male sterile or removed if fertile. This method of developing the pure male sterile isoline is a one-time procedure for a given genotype as subsequent maintainer seed is provided by crossing the original soybean line onto rows of plants of the pure male sterile isoline.
Isoline male sterile seed is produced by crossing pollen from maintainer seed onto male sterile plants from segregating F2 backcrossed seed. When the selectable marker is for an herbicide, the maintainer seed plants must be sprayed with herbicide (e.g., glyphosate) as described for the F1 and F1 backcrosses in the line conversion process and for the same reason. As in the initial production of maintainer seed, the initial male sterile can be made by hand pollination or by insect pollinators of soybean. The fertile plants in the F2 BC rows must be removed by hand as in the process of producing maintainer seed.
Subsequent pure isoline male sterile seed is produced by crossing rows of maintainer plants sprayed with herbicide as outlined previously onto rows of pure isoline male sterile plants by the presence of natural or introduced pollinators.
Several factors require the producer to adjust the rates and/or timing of the herbicide application. Depending on what herbicide is used, the environmental conditions and the genetics of the parent lines, several adjustments are required. With glyphosate, for example, the application rate generally varies from 16 to 32 ounces per acre or more. Timing between applications are adjusted from five or six days to as much as 20 days between sprayings. In addition, the first spraying is typically timed with the presence of the first flower buds on the plants, but earlier spraying applications may be used to increase the effectiveness of spraying techniques.
With quantities of male sterile seed capable of setting economically adequate rates of production one can proceed to produce hybrid soybean seed. If the male soybean line used to produce the hybrid does not carry the same herbicide resistance as the male sterile female (glyphosate resistant female) the seed can be preferably blended approximately 30% male and 70% female (30/70) before planting in the production field. Depending on growing conditions and pollinator activity, it may be necessary to vary the ratio of male to female seed parents in a production field from 30/70 to 40/60 or 50/50 and even higher amounts of male seed. Natural or introduced pollinators (in the case of alfalfa leafcutting bees use approximately 10,000 to 20,000 per acre with a shelter placed in each 4 to 10 acres) are needed to move pollen from the male plants to the male sterile female plants.
In one embodiment, the production field is sprayed with the herbicide to which the female is resistant (glyphosate) at approximately the maximum recommended rate immediately at the end of the flowering period. This eliminates having any male seed in the conditioned hybrid seed production. If the female is not herbicide resistant or does not have resistance different than the male, the production field is planted in alternate rows or male female patterns, such as one to two or one to three, and the male rows are removed or kept separate from the female hybrid seed parent.
Sterile off-type plants in hybrid soybeans may set little or no seed and may be considered more detrimental in soybeans than in a crop such as corn where male sterile plants set normally when mixed with fertile plants. When there is concern about off-types or non-hybrid plants coming from either the male or female parents, they can be reduced by various means. When the male is carrying herbicide resistance different than the female then methods are available to reduce off-type plants. For example, if the male has resistance to STS and the female is susceptible, then the seed can be treated with the herbicide to which the female is susceptible, Chlorsulfuron, when processed in the seed conditioning facilities. This renders any female selfs or off-types as non-competitive (few or no seed produced on these plants) in the growers production field. Another method to have pure production for the grower when the male and female parents of the hybrid have different herbicide resistance; is to spray the fields shortly after emergence with one or the other, or both herbicides to remove at the seedling stage off type plants originating from the male, female or both as the situation allows.
These processes and procedures when integrated as described allow for the development and production of hybrid soybean seed on an economically viable basis.
The present invention is a method for forming seeds capable of yielding F1 hybrid soybean plants (i.e., hybrid soybean plants of the first filial generation) or maintaining male sterile soybean plants useful in the production of male fertile F1 hybrid soybean plants. Male sterile (i.e., seed parents) and the male fertile soybean plants (i.e., pollen parents) are caused to undergo cross-pollination with the aid of pollen-carrying bees. In accordance with one embodiment of the present invention the pollen-carrying bees (e.g., leafcutter bees) facilitates a high level of cross-pollination and seeds are formed on the male sterile soybean plants which ultimately are harvested.
In one aspect of the invention, the female seed parents often retain green leaves after the hybrid seed on the plants is physiologically mature. Physiological maturity generally occurs when the soybean seeds have turned from a green to yellow color. By spraying a defoliant such as paraquat on the female seed plants the green leaves die and are removed approximately 2 or 3 weeks sooner than would naturally occur. This allowed for an earlier harvest (14-20 days), aided the ease of combine harvesting because of better dry down of the plants, and created better seed quality because of the lessened exposure to the elements that the mature seed experienced.
In another aspect of the invention, the female seed parents and male pollinator are harvested together in order to create a hybrid blend. Under normal pollinating conditions this results in a blend that is approximately 70% inbred seed and 30% hybrid seed. The hybrid seed found on the female seed parents is often 20-30% larger than the inbred seed. By screening out up to 35% of the smaller inbred seed, the percentage of hybrid in the blend is shifted towards 40% rather than 30%. For example, a hybrid production field is harvested without removing the male seed parent and results in a hybrid blend containing 70% inbred (male seed parent) and 30% hybrid seed. The seed conditioner may remove a majority of the smaller seeds from the blend. These smaller seeds are nearly all from the male seed parent (inbred line). If the smallest 25% of the total blend is removed through screening, then the resulting blend is, for example, approximately 60% inbred and 40% hybrid seed. This screening method can shift the ratio of inbred to hybrid towards the hybrid component in any blend regardless of the percentages present in the initial harvesting.
Using similar techniques and other techniques well known in the art, other male sterile genes and herbicide resistance genes can also be used in the present invention. The instant invention relates to herbicide resistance genes, constructs, promoters and male sterility genes and to methods of incorporating the resistance and male sterile genes into commercial soybean varieties. Suitable genes, promoters and methods may be found in Herbicide-Resistant Crops, Editor Stephen O. Duke, CRC Lewis Publishers, 1996; Herbicide Resistance in Plants, Editors Stephen B. Powles and Joseph A. M. Holtum, CRC Press Inc., 1994; and in U.S. Pat. Nos. 5,084,082; 5,359,142; 5,322,938; 5,424,200; 5,164,316; 5,352,605; 5,094,945; 4,535,600 and 4,940,835, all of which are incorporated herein by reference.
As used herein, the term xe2x80x9cplantxe2x80x9d includes plant cells, plant protoplasts, plant cells of tissue culture from which soybean plants can be regenerated, plant calli, plant clumps, and plant cells that are intact plants or parts of plants such as pollen, flowers, seeds, leaves, stems and the like.